On Wed, Jan 24, 2018 at 12:05:16PM +0300, Yury Norov wrote:

This series adds API for 128-bit memory IO access and enables it for ARM64.
The original motivation for 128-bit API came from new Cavium network device
driver. The hardware requires 128-bit access to make things work. See
description in patch 3 for details.

Also, starting from ARMv8.4, stp and ldp instructions become atomic, and
API for 128-bit access would be helpful in core arm64 code.

Only for normal, cacheable memory, so they're not suitable for IO accesses
as you're proposing here.

Will